feat(approval): collapse approval modal to a one-line banner with Tab

Previously the approval modal rendered as a full-screen takeover
card that hid the transcript behind it, so users had to dismiss the
prompt — losing the decision context — just to re-read the tool
call they were being asked to approve. The new collapsed mode flips
the modal to a single-line banner pinned at the bottom of the area
("<tool> — <risk badge>  [Tab to expand]"), so the conversation
stays visible while the decision is pending. Tab toggles between
the two modes; the selected option, pending-confirm state, and
risk colour scheme are preserved across the toggle.

Test pin: a fresh `ApprovalView` starts expanded, the first Tab
collapses, the second Tab restores — and both return `ViewAction::None`
so no decision side effect leaks out of the toggle.

Harvested from PR #1455 by @tiger-dog

Note for the maintainer: PR #1455 also includes a Chinese-language
preamble to `prompts/base.md` that biases reasoning_content toward
Chinese on Chinese-language turns. That change touches the system
prompt and is left for a separate sign-off — see
.private/handoffs/v0.8.32-1455-prompt-preamble.md for the diff and
the suggested call.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -16,6 +16,15 @@ real world uses."
 
 ### Fixed
 
+- **Approval modal can be collapsed to a one-line banner with
+  Tab** (harvested from PR #1455 by **@tiger-dog**). Previously the
+  approval prompt rendered as a full-screen takeover that hid the
+  transcript behind it, so users had to dismiss the modal just to
+  remember which tool call they were being asked to approve. Tab
+  now toggles between the takeover card and a single-line bottom
+  banner — the rest of the conversation stays visible while the
+  decision is pending. Tab again restores the full card; the
+  selection state is preserved across the toggle.
 - **Markdown renderer no longer eats underscores inside
   identifiers** (harvested from PR #1455 by **@tiger-dog**). The
   inline parser was matching `_italic_` against the underscore in

crates/tui/src/tui/approval.rs

@@ -504,6 +504,8 @@ pub struct ApprovalView {
     pending_confirm: Option<ApprovalOption>,
     timeout: Option<Duration>,
     requested_at: Instant,
+    /// Whether the approval card is collapsed to a single-line banner.
+    pub(crate) collapsed: bool,
 }
 
 impl ApprovalView {
@@ -520,6 +522,7 @@ impl ApprovalView {
             pending_confirm: None,
             timeout: None,
             requested_at: Instant::now(),
+            collapsed: false,
         }
     }
 
@@ -625,6 +628,10 @@ impl ModalView for ApprovalView {
 
     fn handle_key(&mut self, key: KeyEvent) -> ViewAction {
         match key.code {
+            KeyCode::Tab => {
+                self.collapsed = !self.collapsed;
+                ViewAction::None
+            }
             KeyCode::Up | KeyCode::Char('k') => {
                 self.select_prev();
                 ViewAction::None
@@ -1153,6 +1160,28 @@ mod tests {
         assert_eq!(view.risk(), RiskLevel::Benign);
     }
 
+    #[test]
+    fn tab_toggles_collapsed_card_so_transcript_stays_visible() {
+        // Regression for PR #1455 / @tiger-dog: the approval modal
+        // rendered as a full-screen takeover that hid the transcript
+        // behind it, so users had to dismiss the prompt to remember
+        // what they were approving. Tab now flips between the full
+        // takeover card and a single-line bottom banner.
+        let mut view = ApprovalView::new(benign_request());
+        assert!(
+            !view.collapsed,
+            "modal must start expanded so first-time users notice it"
+        );
+
+        let action = view.handle_key(create_key_event(KeyCode::Tab));
+        assert!(matches!(action, ViewAction::None));
+        assert!(view.collapsed, "first Tab collapses the card");
+
+        let action = view.handle_key(create_key_event(KeyCode::Tab));
+        assert!(matches!(action, ViewAction::None));
+        assert!(!view.collapsed, "second Tab restores the takeover card");
+    }
+
     #[test]
     fn test_approval_view_navigation() {
         let mut view = ApprovalView::new(benign_request());

crates/tui/src/tui/widgets/mod.rs

@@ -1010,6 +1010,31 @@ impl Renderable for ApprovalWidget<'_> {
             return;
         }
 
+        // Collapsed mode: a single-line banner at the bottom of the area
+        // so the user can still see the transcript behind it.
+        if self.view.collapsed {
+            let bar_y = area.y.saturating_add(area.height.saturating_sub(1));
+            let bar_area = Rect::new(area.x, bar_y, area.width, 1);
+            Clear.render(bar_area, buf);
+
+            let risk = self.request.risk;
+            let palette_colors = approval_palette(risk);
+            let summary = format!(
+                " {} — {}  [Tab to expand] ",
+                self.request.tool_name,
+                risk_badge_text(risk, self.view.locale()),
+            );
+            let line = Line::from(Span::styled(
+                summary,
+                Style::default()
+                    .fg(palette::DEEPSEEK_INK)
+                    .bg(palette_colors.accent)
+                    .add_modifier(Modifier::BOLD),
+            ));
+            Paragraph::new(line).render(bar_area, buf);
+            return;
+        }
+
         let card_area = compute_takeover_area(area);
         Clear.render(card_area, buf);